Control Bosch 4300iW Boiler with Home Assistant EMS-ESP32 - Help

Hi everyone,
I’m new to Home Assistant and looking to integrate my Bosch Condens 4300iW boiler with the system. I didn’t purchase the CT200 thermostat because it’s too expensive, but I’ve read that it’s possible to control the boiler via Home Assistant in a more cost-effective way, and I’d love to give it a try.

Current setup

  • Boiler: Bosch Condens 4300iW, installed in an outdoor cabinet (Wi-Fi signal is strong).
  • EMS Interface Board: Purchased the BBQKees v3.1 model.
  • Conduit: There’s a conduit connecting the boiler to a hole in the indoor wall (originally intended for a thermostat).
  • Plan: Place the EMS Interface Board and an ESP32 in the outdoor cabinet (inside a 3D-printed box) or inside the wall hole for the thermostat.

Project goals

  1. Integration with Home Assistant:
  • Monitor and control the boiler’s temperature.
  • Turn radiators on/off.
  • Use advanced boiler features (flame modulation, energy-saving).
  1. Indoor temperature sensor:
  • Add an indoor temperature sensor (Wi-Fi or Zigbee). I’m unsure whether to wire it to the ESP32 or use a battery-powered wireless sensor for more flexibility.
  1. Touch display (future):
  • Install a touch display in the thermostat hole to monitor boiler data and control functions. I’m not sure if this requires a wired connection to the ESP32 or if wireless options exist.

Questions

  1. EMS + ESP32: Is it feasible to place both boards in the boiler’s outdoor cabinet? Will Wi-Fi be reliable for communication with Home Assistant, or would it be better to install them indoors in the thermostat hole?
  2. Indoor sensor: What’s the simplest and most effective solution: a battery-powered sensor (Wi-Fi/Zigbee) or one wired directly to the ESP32?
  3. Touch display: Does a touch display need to be wired to the ESP32, or can it be integrated wirelessly?
  4. Choosing the ESP32: Which ESP32 model would be best suited for this project?

Thank you very much for any advice or guidance! I’m eager to learn and make my home smarter with Home Assistant.